Power Units with Manual Override Controls for Hydraulic Systems

ABSTRACT

A power unit with manual override control for a hydraulic system having an initial state and at least one operational state is provided, comprising: a tank for storing hydraulic fluid that moves between a first chamber and a second chamber of a hydraulic cylinder; a pump that routes the hydraulic fluid in and out of the tank; a first relief valve; a first solenoid valve configured to shift between a plurality of positions based on the at least one operational state of the hydraulic system; a first check valve connected to the first solenoid valve; a manual override control unit comprising: a second check valve; and a second solenoid valve configured to shift between a plurality of positions based on activation of a manual override control, wherein the activation of the manual override control returns the hydraulic system from the at least one operational state to the initial state.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Nonprovisional applicationSer. No. 16/984,958, filed on Aug. 4, 2020, which is a continuation ofU.S. Nonprovisional application Ser. No. 16/458,914, filed on Jul. 1,2019, now U.S. Pat. No. 10,760,599, issued on Sep. 1, 2020, which claimsbenefit of U.S. Provisional Application Ser. No. 62/692,569, filed onJun. 29, 2018. The entire contents of the priority applications arehereby incorporated by reference as if fully set forth herein.

FIELD OF THE INVENTION

The present invention generally relates to hydraulics and morespecifically to power units with manual override controls for hydraulicsystems.

BACKGROUND

Hydraulics is a technology that dates back for many centuries andincludes the use of liquids (i.e., hydraulic fluid) in the applicationof mechanical properties. At its core, hydraulics may be used for thegeneration, control, and transmission of power by the use of pressurizedhydraulic fluids. Typically, hydraulic fluid is the medium by whichpower is transferred in hydraulic devices and/or systems. Commonhydraulic fluids may be based on mineral oil or water. In practice,hydraulic devices and/or systems may be central parts of varioustechnologies, such as but not limited to, hydraulic brakes, powersteering systems, aircraft flight control systems, lifts, dump trucks,and various other mobile and industrial machinery.

SUMMARY OF THE INVENTION

The various embodiments of the present hydraulic power units with manualoverride controls contain several features, no single one of which issolely responsible for their desirable attributes. Without limiting thescope of the present embodiments, their more prominent features will nowbe discussed below. In particular, the present hydraulic power unitswith manual override controls will be discussed in the context of atruck bed equipped with a hydraulic lift (may also be referred to as“dump truck”) or a dump trailer that is also known as bumper pull dumptrailer, dump trailer, or hydraulic tipper. However, the use of a dumptruck/dump trailer is merely exemplary and the present hydraulic powerunits with manual override controls may be utilized for a variety ofhydraulic applications as appropriate to the requirements of a specifichydraulic system (may also be referred to as a “hydraulic device”) inaccordance with various embodiments of the invention. After consideringthis discussion, and particularly after reading the section entitled“Detailed Description,” one will understand how the features of thepresent embodiments provide the advantages described here.

One aspect of the present embodiments includes the realization that incurrent hydraulic systems other than the present embodiments, ahydraulic power unit may malfunction when the hydraulic system isoutside a resting state (may also be referred to as “initial state”). Insuch situations, current hydraulic systems other than the presentembodiments may require a hydraulic professional to service thehydraulic device or risk overflowing the hydraulic fluid by forcing thehydraulic system back to its initial state. For example, a power unitthat controls a hydraulic cylinder used to raise and lower a truck bedor dump bed may lose power or short circuit. If the power unitmalfunctions when the truck bed is in a raised position, the truck bedmay be stuck in the raised position. Likewise, if a car lift is in araised position and the power unit malfunctions, a car may be stuck inthe raised position until the power unit can be fixed. In certainapplications, power unit malfunctions may be more than justinconvenient. For example, if a wheelchair lift is stuck in a raisedposition, a person may be stuck in a precarious position that may beextremely dangerous. The present embodiments solve these problem byproviding manual override (e.g., manual lowering) controls for hydraulicpower units and/or hydraulic systems. The present embodiments thusadvantageously enable returning a hydraulic device to an initial restingposition without damaging the hydraulic device. The present embodimentsprovide these advantages and enhancements, as described below.

In a first aspect, a power unit with manual override control for ahydraulic system having an initial state and at least one operationalstate is provided, the power unit comprising: a tank for storinghydraulic fluid that moves between a first chamber and a second chamberof a hydraulic cylinder, wherein the first chamber of the hydrauliccylinder is connected to an A port of the power unit that is configuredto allow the hydraulic fluid to enter and exit the first chamber, andthe second chamber of the hydraulic cylinder is connected to a B port ofthe power unit that is configured to allow the hydraulic fluid to enterand exit the second chamber; a pump connected to a motor having apowered on and a powered off configuration, wherein the motor providespower to the pump to route the hydraulic fluid in and out of the tank inmoving the hydraulic fluid between the first chamber and second chamberof the hydraulic cylinder; a first relief valve connected to the pump,wherein the first relief valve is configured to open when pressureacross the first relief valve reaches a first relief valve setting; afirst solenoid valve connected to the pump, wherein the first solenoidvalve is configured to shift between a plurality of positions based onthe at least one operational state of the hydraulic system; a firstcheck valve connected to the first solenoid valve, wherein the firstcheck valve allows the hydraulic fluid to flow in one direction andblocks flow in the opposite direction so long as pressure across thefirst check valve is below a first check valve setting; a second reliefvalve connected to the first solenoid valve, wherein the second reliefvalve is configured to open when pressure across the second relief valvereaches a second relief valve setting; a manual override control unitcomprising: a second check valve, wherein an open end of the secondcheck valve is connected to the first solenoid valve, and a closed endof the second check valve is connected to the B port, wherein the secondcheck valve is configured to allow hydraulic fluid to flow in onedirection and block flow in the opposite direction so long as pressureacross the second check valve is below a second check valve setting; anda second solenoid valve connected to the A port, wherein the secondsolenoid valve is configured to shift between a plurality of positionsbased on activation of a manual override control, wherein the activationof the manual override control returns the hydraulic system from the atleast one operational state to the initial state.

In an embodiment of the first aspect, the plurality of positions of thesecond solenoid valve includes a first position that loads a controlcheck valve and a second position that loads a controlsingle-directional connector.

In another embodiment of the first aspect, the closed end of the secondcheck valve is connected to a closed end of the first check valve.

In another embodiment of the first aspect, the closed end of the secondcheck valve is connected to a third relief valve that connects to thetank.

In another embodiment of the first aspect, wherein in the initial state:the second solenoid valve is in the first position thereby loading thecontrol check valve and connecting the A port to a closed end of thecontrol check valve; and the first solenoid valve is in a firstposition, wherein the first position of the first solenoid valveconnects the pump to the open end of the second check valve of themanual override control unit.

In another embodiment of the first aspect, the hydraulic fluid in thefirst chamber is blocked from moving by the closed end of the controlcheck valve and the hydraulic fluid in the second chamber is blockedfrom moving by the closed end of the second check valve, the closed endof the first check valve, and the third relief valve.

In another embodiment of the first aspect, the at least one operationalstate includes an extending state, wherein in the extending state: thesecond solenoid valve is in the first position thereby loading thecontrol check valve; the first solenoid valve is in a second position,wherein the second position of the first solenoid valve connects thepump to the open end of the control check valve; and the motor is in thepowered on confirmation providing power to the pump to route thehydraulic fluid from the pump to the open end of the control checkvalve.

In another embodiment of the first aspect, the hydraulic fluid exits theA port to the first chamber of the hydraulic cylinder thereby placingthe hydraulic system in the extending state.

In another embodiment of the first aspect, the hydraulic fluid is pushedout of the second chamber and is routed through: the closed end of thesecond check valve by overcoming the second check valve setting; thefirst solenoid valve; and the second relief valve by overcoming thesecond relief valve setting thereby allowing the hydraulic fluid to flowfrom the second chamber to the tank.

In another embodiment of the first aspect, the at least one operationalstate includes a retracting state, wherein in the retracting state: thesecond solenoid valve is in second position thereby loading the controlsingle-directional connector; the first solenoid valve is in the firstposition, wherein the first position of the first solenoid valveconnects the pump to the closed end of the second check valve; and themotor is in the powered on confirmation providing power to the pump toroute the hydraulic fluid from the tank to the first solenoid valve.

In another embodiment of the first aspect, the hydraulic fluid exits theB port to the second chamber of the hydraulic cylinder thereby placingthe hydraulic system in the retracting state.

In another embodiment of the first aspect, the hydraulic fluid is pushedout of the first chamber and is routed through: the controlsingle-directional connector; the first solenoid valve; and the secondrelief valve by overcoming the second relief valve setting therebyallowing the hydraulic fluid to flow from the first chamber to the tank.

In another embodiment of the first aspect, wherein when the manualoverride is activated: the second solenoid valve is in the secondposition thereby loading the control single-directional connector; andthe first solenoid valve is in the first position, wherein the firstposition of the first solenoid valve connects the controlsingle-directional connector to the second relief valve and the open endof the first check valve.

In another embodiment of the first aspect, the hydraulic fluid is pushedout of the first chamber due to gravity.

In another embodiment of the first aspect, the hydraulic fluid is pushedout of the first chamber due to a weight of a load.

In another embodiment of the first aspect, the hydraulic fluid in thefirst chamber is routed through: the control single-directionalconnector; and the first solenoid valve in its first position thatdirects the hydraulic fluid through the first solenoid valve to thefirst check valve.

In another embodiment of the first aspect, the second chamber creates alow pressure vacuum which allows for the hydraulic fluid to be routedout of the B port and into the second chamber.

In another embodiment of the first aspect, wherein an internal pressurewithin the second chamber builds to overcome the second relief valvesetting thereby allowing any remainder of the hydraulic fluid from thefirst chamber to return to the tank without overflowing the hydraulicsystem.

In another embodiment of the first aspect, the manual override controlis activated by an override input device directly connected to the powerunit.

In another embodiment of the first aspect, the manual override controlis activated by an override input device wirelessly connected to thepower unit.

In a second aspect, a manual override control unit for returning ahydraulic system to an initial state is provided, the manual overridecontrol unit comprising: an override input device; a solenoid valveconfigured to connect to the hydraulic system, wherein the solenoidvalve shifts between a first position and a second position, wherein thefirst position of the solenoid valve loads a control check valve havingan open end and a closed end, and wherein the second position of thesolenoid valve loads a control single-directional connector; and whereinthe activation of the override input device returns the hydraulic systemto the initial state.

In an embodiment of the second aspect, the manual override control unitfurther comprises a check valve comprising an open end and a closed end,wherein the closed end of the check valve is configured to connect tothe hydraulic system and wherein the check valve is configured to allowhydraulic fluid to flow in one direction and block flow in an oppositedirection so long as pressure across the check valve is below a checkvalve setting.

In another embodiment of the second aspect, the hydraulic systemcomprises a hydraulic cylinder comprising a first chamber and a secondchamber.

In another embodiment of the second aspect, the solenoid valve isconfigured to connect to the first chamber of the hydraulic cylinder andthe closed end of the check valve is configured to connect to the secondchamber of the hydraulic cylinder.

In another embodiment of the second aspect, the hydraulic cylinderincludes an extending state.

In another embodiment of the second aspect, wherein in the extendingstate the solenoid valve is in the first position thereby loading thecontrol check valve, and wherein the closed end of the control checkvalve is configured to connect to the first chamber.

In another embodiment of the second aspect, the hydraulic fluid isrouted through the open end of the control check valve and enters thefirst chamber of the hydraulic cylinder.

In another embodiment of the second aspect, the hydraulic fluid exitsthe second chamber and is routed through the closed end of the checkvalve by overcoming the check valve setting.

In another embodiment of the second aspect, the hydraulic cylinderincludes a retracting state.

In another embodiment of the second aspect, wherein in the retractingstate the solenoid valve is in the second position thereby loading thecontrol single-directional connector.

In another embodiment of the second aspect, the hydraulic fluid isrouted through the open end of the check valve and enters the secondchamber of the hydraulic cylinder.

In another embodiment of the second aspect, the hydraulic fluid exitsthe first chamber and is routed through the control single-directionalconnector.

In another embodiment of the second aspect, wherein when the overrideinput device is activated, the solenoid valve is in the second positionthereby loading the control single-directional connector.

In another embodiment of the second aspect, the hydraulic fluid exitsthe first chamber with assistance from gravity.

In another embodiment of the second aspect, the hydraulic fluid exitingthe first chamber is routed through the control single-directionalconnector.

In another embodiment of the second aspect, the hydraulic fluid exitingthe first chamber creates a low pressure vacuum in the second chamber.

In another embodiment of the second aspect, the low pressure vacuum inthe second chamber causes the hydraulic fluid to enter the secondchamber.

In another embodiment of the second aspect, wherein an internal pressurewithin the second chamber increases to overcome at least one reliefvalve setting to allow hydraulic fluid to exit from the first chamberwithout overflowing the hydraulic system.

In another embodiment of the second aspect, the override input device isactivated via a direct connection.

In another embodiment of the second aspect, the override input device isactivated via a wireless connection.

In a third aspect, a power unit with manual override control for ahydraulic device having an initial state is provided, the power unitcomprising: a tank for storing hydraulic fluid that moves between afirst chamber and a second chamber of the hydraulic device; a pumpconfigured to connect to a motor having a powered on and a powered offconfiguration, wherein the motor provides power to the pump to route thehydraulic fluid in and out of the tank in moving the hydraulic fluidbetween the first chamber and second chamber of the hydraulic device;and a manual override control unit, wherein activation of the manualoverride control unit returns the hydraulic device to the initial state.

In an embodiment of the third aspect, the power unit further comprisesan A port, wherein the A port is configured to connect to the firstchamber of the hydraulic device to allow the hydraulic fluid to enterand exit the first chamber and a B port, wherein the B port isconfigured to connect to the second chamber of the hydraulic device toallow the hydraulic fluid to enter and exit the second chamber.

In another embodiment of the third aspect, the manual override controlunit comprises a solenoid valve configured to connect to the firstchamber of the hydraulic device, wherein the solenoid valve includes afirst position and a second position.

In another embodiment of the third aspect, the first position of thesolenoid valve loads a control check valve having an open end and aclosed end.

In another embodiment of the third aspect, the second position of thesolenoid valve loads a control single-directional connector.

In another embodiment of the third aspect, the activation of the manualoverride control unit shifts the solenoid valve between the firstposition and the second position.

In another embodiment of the third aspect, the activation of the manualoverride control unit causes hydraulic fluid to exit the first chamber.

In another embodiment of the third aspect, the hydraulic fluid exits thefirst chamber with assistance from gravity.

In another embodiment of the third aspect, the hydraulic fluid exitingthe first chamber is routed to the tank.

In another embodiment of the third aspect, the hydraulic fluid exitingthe first chamber creates a low pressure vacuum in the second chamber.

In another embodiment of the third aspect, the low pressure vacuum inthe second chamber causes the hydraulic fluid to enter the secondchamber.

In another embodiment of the third aspect, an internal pressure withinthe second chamber increases to apply pressure for the hydraulic fluidto route to the tank.

In another embodiment of the third aspect, the power unit furthercomprises at least one relief valve, wherein the at least one reliefvalve is configured to open when pressure across the at least one reliefvalve reaches a relief valve setting of the at least one relief valve.

In another embodiment of the third aspect, the hydraulic fluid exitingthe first chamber creates pressure to overcome the relief valve settingof the at least one relief valve allowing hydraulic fluid to route tothe tank.

In another embodiment of the third aspect, the manual override controlunit further comprises a check valve comprising an open end and a closedend, wherein the closed end of the check valve is configured to connectto the second chamber of the hydraulic device and wherein the checkvalve is configured to allow hydraulic fluid to flow in one directionand block flow in an opposite direction so long as pressure across thecheck valve is below a check valve setting.

In another embodiment of the third aspect, the power unit furthercomprises a solenoid valve connected to the pump having a first positiona second position.

In another embodiment of the third aspect, the solenoid valve connectedto the pump connects the pump to the open end of the check valve whenthe manual override control unit is activated.

In another embodiment of the third aspect, the manual override controlunit further comprises an override input device.

In another embodiment of the third aspect, the override input device isactivated via a direct connection.

In another embodiment of the third aspect, the override input device isactivated via a wireless connection.

BRIEF DESCRIPTION OF THE DRAWINGS

The various embodiments of the present hydraulic power units with manuallowering controls now will be discussed in detail with an emphasis onhighlighting the advantageous features. These embodiments depict thenovel and non-obvious hydraulic power units with manual loweringcontrols shown in the accompanying drawings, which are for illustrativepurposes only. These drawings include the following figures:

FIG. 1 illustrates a dump truck/trailer utilizing a dual-actinghydraulic cylinder for lifting a truck bed in accordance with anembodiment of the invention.

FIGS. 2A-C illustrate a dual-acting hydraulic cylinder in various statesrelative to positions of a truck bed in accordance with an embodiment ofthe invention.

FIG. 3 illustrates a hydraulic power unit with manual lowering controlin accordance with an embodiment of the invention.

FIG. 4 is a schematic diagram illustrating a hydraulic power unit withmanual lowering control when a hydraulic cylinder is at rest (e.g., allcartridge valves are at de-energized position or also known as neutralstate) in accordance with an embodiment of the invention.

FIG. 5 is a schematic diagram illustrating a hydraulic power unit withmanual lowering control when a hydraulic cylinder is raising atruck/trailer bed in accordance with an embodiment of the invention.

FIG. 6 is a schematic diagram illustrating a hydraulic power unit withmanual override control when a hydraulic cylinder is lowering a truckbed in accordance with an embodiment of the invention.

FIG. 7 is a schematic diagram illustrating a powerless hydraulic powerunit with manual override control activated to lower a truck bed inaccordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

The following detailed description describes the present embodimentswith reference to the drawings. In the drawings, reference numbers labelelements of the present embodiments. These reference numbers arereproduced below in connection with the discussion of the correspondingdrawing features.

Turning now to the drawings, hydraulic power units with manual overridecontrols (may also be referred to as “power units”) in accordance withembodiments of the invention are disclosed. In many embodiments,hydraulic power units with manual override controls may be connected toone or more hydraulic devices, such as but not limited to a hydrauliccylinder. In various embodiments, the hydraulic power units with manualoverride controls may be part of a larger hydraulic system. In severalembodiments, hydraulic power units with manual override controls mayinclude a manifold connected to a motor (e.g., DC powered motor) thatpowers a pump for regulating fluid flow between various components inthe hydraulic system, as further described below. In many embodiments,the hydraulic power units may include a manual override control unitthat allows an operator to override the hydraulic system's current stateand return the system back to an initial state. Hydraulic systemsutilizing dual-acting cylinders in accordance with embodiments of theinvention are further discussed below.

Dump Trucks with Dual-Acting Hydraulic Cylinders

A variety of systems may use hydraulic cylinders to provide adirectional force using pressurized hydraulic fluid (may also bereferred to as “fluid”). Typically, a hydraulic cylinder may include acylinder barrel in which a piston is connected to a piston rod that maymove back and forth as the piston moves back and forth within thecylinder barrel. By connecting the piston rod to an external structure,the force generated by the pressurized hydraulic fluid may be applied tothe external structure. In dual-acting hydraulic cylinders, thehydraulic barrel may include a first chamber (blind end or barrel end)and a second chamber (may also be referred to as “rod end”) separated bythe piston, where the first chamber may have a first pressure level andthe second chamber may have a second pressure level. As furtherdescribed below, the first and second chambers may be connected by ahydraulic power unit with manual override control configured to move thehydraulic fluid between the first and second chambers.

A dump truck utilizing a dual-acting hydraulic cylinder for lifting atruck trailer bed in accordance with an embodiment of the invention isillustrated in FIG. 1. The dump truck 100 may include a dual-actinghydraulic cylinder 102 for lifting a truck bed 104. The dump truck 100may also include a frame 110 having a bar 112 that connects to one sideof the hydraulic cylinder 102 (may also be referred to as “blind end”).One of ordinary skill in the art would recognize that Direct Push andScissor Hoist are two common methods of raising the dump bed (shown inFIG. 1 is a Scissor Hoist). In addition, the truck bed 104 may beconnected to a frame 106 that attaches to a lift arm having a firstportion 114, a joint 116, and a second portion 118. In variousembodiments, a piston rod may extend from a rod end of the hydrauliccylinder 102 and connect to the second portion 118 of the lift arm. Inseveral embodiments, the lift arm may be configured to receive forcefrom the hydraulic cylinder 102 via the piston rod to raise or lower thetruck bed 104, as further described below.

As described above, a dual-acting hydraulic cylinder may have twochambers (e.g., a first chamber barrel or blind end and a second chamberor rod end) that may be connected by a power unit for moving hydraulicfluid between the chambers for raising or lowering the truck bed 104.For example, the first chamber may have a first port (may also bereferred to as “bottom port”) that connects to a corresponding firstport of the power unit (may also be referred to as “A port”) forallowing the hydraulic fluid to enter and exit the first chamber.Further, the second chamber may also include a second port (may also bereferred to as “top port”) that connects to a corresponding second portof the power unit (may also be referred to as “B port”) for allowing thehydraulic fluid to enter and exit the second chamber.

A dual-acting hydraulic cylinder in various states relative to positionsof a truck bed in accordance with an embodiment of the invention isillustrated in FIGS. 2A-C. In reference to FIG. 2A, the truck bed 216 islevel and the hydraulic cylinder 202 is in its initial state. In manyembodiments, the hydraulic cylinder 202 may include a first chamber 204and a second chamber 206 separate by a piston 208. The piston 208 may beconnected to a piston rod 210 that extends out from the second chamber206 to attach to a structural device (not illustrated, such as but notlimited to a lift arm) connected to the truck trailer bed 216 ordirectly to the truck bed 216. In addition, the first chamber 204 mayhave a bottom port connected to a first hydraulic tube 212 (may also bereferred to as “first hose”) that connects to an A port of a power unit,as further described below. Likewise, the second chamber 206 may have atop port connected to a second hydraulic tube 214 (may also be referredto as “second hose”) that connects to a B port of a power unit, asfurther described below. In the initial state, the piston may bepositioned such that the amount of hydraulic fluid in the first chamber204 is less than when the hydraulic cylinder is in operation. Forillustrative purposes, the hydraulic fluid in the first chamber 204 isshown relatively smaller than the hydraulic fluid in the second chamber206.

In reference to FIG. 2B, the hydraulic cylinder 202 is raising the truckbed 216. In such embodiments, the hydraulic fluid is transferred fromsecond chamber 206 to the first chamber 204 via the power unit (notillustrated) resulting in the piston 208 and thus the piston rod 210actuating (e.g., extending) and thus lifting the truck bed 216. Duringthe process of lifting, the piston 208 moves such that the piston rod210 extends out and away from the rod end of the hydraulic cylinder 202.In many embodiments, the raising process may be initiated by an operatorproviding an input to the power unit, such as but not limited to,pressing an “up” button, as further described below. The user may stopthe raising process by providing an input to the power unit, such as butnot limited to, releasing the up button. In such embodiments, the powerunit may stop the movement of the hydraulic fluid from the secondchamber 206 and the first chamber 204 and thus the truck bed 216 may bestopped at a particular position.

In reference to FIG. 2C, the hydraulic cylinder 202 is lowering thetruck bed 216. In such embodiments, the hydraulic fluid is transferredfrom first chamber 204 to the second chamber 206 via the power unit (notillustrated) resulting in the piston 208 and thus the piston rod 210retracting and thus lowering the truck bed 216. During the process oflowering, the piston 208 moves such that the piston rod 210 retractstowards the blind end of the hydraulic cylinder 202. In manyembodiments, the lowering process may be initiated by an operatorproviding an input to the power unit, such as but not limited to,pressing a “down” button, as further described below. The user may stopthe lowering process by providing an input to the power unit, such asbut not limited to, releasing the down button. In such embodiments, thepower unit may stop the movement of the hydraulic fluid from the firstchamber 204 to the second chamber 206 and thus the truck bed 216 may bestopped at a particular position.

Although specific hydraulic systems for dump trucks using dual-actinghydraulic cylinders are discussed above with respect to FIGS. 1-2C, anyof a variety of systems using various hydraulic devices as appropriateto the requirements of a specific application can be utilized inaccordance with embodiments of the invention. Power units with manualoverride controls in accordance with embodiments of the invention arediscussed further below.

Power Units with Manual Override Controls

Hydraulic power units may be connected to hydraulic cylinders to drivethe movement of pistons within a cylinder barrel. Further, power unitsin accordance with embodiments of the invention may include a manualoverride control to return a hydraulic cylinder to an initial state whenthe power unit is malfunctioning.

A hydraulic power unit with manual override control in accordance withan embodiment of the invention is illustrated in FIG. 3. The power unit300 may include manifold 316 having an A port 309 that connects to acorresponding bottom port of a hydraulic cylinder via a first hose, asdescribed above. Likewise, the manifold 316 may include a B port 310that connects to a corresponding top port of a hydraulic cylinder, asdescribed above. In many embodiments, the power unit 300 may alsoinclude a tank 307 that connects to a pump (not illustrated) that may bedriven by a motor 308. In some embodiments, the pump may be built intothe tank 307 or connected to the tank 307. In several embodiments, thepump may be a hydraulic gear pump and the motor 308 may be an electricDC powered motor. In operation, the motor 308 may turn the pump (notillustrated) and the pump push hydraulic fluid out of the tank 307 formoving hydraulic fluid between the first and second chambers of adual-acting hydraulic cylinder, as further described below. In variousembodiments, the tank 307 may also act as a reservoir for receivinghydraulic fluid within the system. The power unit 300 may include acontroller 313 having an up button 314 and a down button 315, asdescribed above. In many embodiments, the up button 314 may configurethe power unit 300 to raise the truck bed and the down button 315 mayconfigure the power unit 300 to lower the truck bed.

In further reference to FIG. 3, the manifold 316 may include a firstrelief valve 301 (may also be referred to as “main relief valve”) thatmay be normally closed but configured to open if the pressure across thefirst relief valve 301 reaches a valve setting. For example, the firstrelief valve 301 may be an adjustable cartridge relief valve that mayhave an adjustable valve setting from 1 pound per square inch (“PSI”) to5000 PSI. The manifold 316 may also include a first solenoid valve 302that may shift between two or more positions based on an operatorsdesired functionality of the hydraulic cylinder (e.g. raise or lower).For example, the first solenoid valve 302 may be a cartridge 4-way,2-position solenoid valve (or in some cases, a cartridge 4-way,3-position solenoid valve) that may take a first position when raisingthe truck bed and take a second position when lowering the truck bed, asfurther described below. In some embodiments, the first solenoid valve302 may be a separate component connected to the manifold 316 or may bean integral part of the manifold 316. The manifold 316 may also includea first check valve 305 that allows hydraulic fluid to flow in onedirection but blocks flow in the opposite direction so long as pressureacross the first check valve 305 is below a valve setting, as furtherdescribed below. In some embodiments, the first check valve 305 may be acartridge check valve with a valve setting 1 PSI to 3000 PSI. Themanifold 316 may include additional hydraulic components, such as butnot limited to, a second relief valve (not illustrated) that may be acartridge relief valve adjustable from 1 PSI to 5000 PSI and/or a thirdrelief valve (not illustrated) that may be a cartridge relief valveadjustable from 1 PSI to 5000 PSI.

In further reference to FIG. 3, the manifold 316 may also include amanual override control unit 303 for lowering the truck bed when thepower unit malfunctions. In many embodiments, the control unit 303 mayinclude a second solenoid valve (not illustrated) (may also be referredto as “cartridge A & B port load holding solenoid valve”) with a manualoverride function, as further described below. The control unit 303 mayfurther include a second check valve (not illustrated). In variousembodiments, the manual override function may be activated by anoverride input device 311, such as but not limited to, a button, a twistcap, etc. In some embodiments, the override input device 311 may bedirectly connected (e.g., via wires) to the control unit 303 or may beconnected wireless using a variety of methods known to one of skill inthe art, such as but not limited to, Bluetooth or WiFi. In furtherreference to the control unit 303, the second solenoid valve may includea first position that allows the truck bed to maintain a static position(e.g., initial state) or to be raised, as further described below.Moreover, the second solenoid valve 303 may include a second positionthat allows the truck bed to be lowered, as further described below. Inaddition, an operator may activate the manual override function usingthe override input device 311 and thereby place the second solenoidvalve 303 in the second position to lower the truck bed, as furtherdescribed below.

Although specific power units with manual override controls arediscussed above with respect to FIG. 3, any of a variety of power unitswith manual override controls including power units with a variety ofhydraulic components as appropriate to the requirements of a specificapplication can be utilized in accordance with embodiments of theinvention. Further, although specific hydraulic components areillustrated as part of or connected to other components, the varioushydraulic components may be either a part of or connected to othercomponents as appropriate to the requirements of a specificationapplication in accordance with embodiments of the invention. Power unitsat initial states in accordance with embodiments of the invention arediscussed further below.

Hydraulic Power Units with Manual Override Controls at Initial States

As described above, a power unit may include a motor, pump, tank, andvarious hydraulic components for moving hydraulic fluid between firstand second chambers of a dual-acting hydraulic cylinder. In the initialstate, the power unit typically is not providing power to the hydrauliccylinder and the truck bed is static in the fully lowered position.

A schematic diagram illustrating a hydraulic power unit with manualoverride control at an initial state in accordance with an embodiment ofthe invention is illustrated in FIG. 4. The schematic diagram 400 of thepower unit is shown connected to a hydraulic cylinder 202 with a truckbed 216 in a fully lowered position. In the initial resting state, amotor 408 is not powered and a pump 407B that may push hydraulic fluidfrom a tank 407A and between the first chamber and the second chamber ofthe hydraulic cylinder is not activated. In various embodiments, thepump 407B may route fluid to a first relief valve 401. The pump 407B mayalso be connected to a first solenoid valve 402 having a first position452 and a second position 453, as further described below. In theinitial state, the first solenoid valve 402 may be in the first position452 connecting the pump 407B to an open end (i.e., free flow directionend) of a second check valve 403B of a manual override control unit 403.In many embodiments, the closed end (i.e., blocked flow direction) ofthe second check valve 403B may be connected to a B port 410 via asecond hose. In some embodiments, the closed end of the second checkvalve 403B may also be connected to a closed end of a first check valve405. In some embodiments, the closed end of the second check valve 403Bmay also be connected to a third cartridge relief valve 406 thatconnects to the tank 407A.

In further reference to FIG. 4, the first chamber may be connected tothe power unit by connecting a bottom port of the hydraulic cylinderwith an A port 409 of the power unit via a first hose. In manyembodiments, the A port 409 may be connected to a second solenoid valve403A of the manual override control unit 403, wherein the solenoid valve403A may have a first position and a second position. In variousembodiments, the first position may include loading a control checkvalve 450 for the second solenoid valve 403A and the second positionthat may loading a control single-directional connector 451 for thesecond solenoid valve 403A. In the initial state, the second solenoidvalve 403A may be in the first position and thus connect the A port 409to a closed end of the control check valve 450. In this configuration,the hydraulic cylinder 202 is kept static since the hydraulic fluid inthe first chamber is blocked from moving by the control check valve 450of the solenoid 403A in its first position and the hydraulic fluid inthe second chamber is blocked from moving by the closed end of thesecond check valve 403B, the closed end of the first check valve 405,and the third relief valve 406. In various embodiments, the control unit403 may also include an override input device 411, as further describedbelow.

Although specific hydraulic power units with manual override controls atinitial states for dump trucks are discussed above with respect to FIG.4, any of a variety of hydraulic power units with manual overridecontrols including power units with manual override controls for varioushydraulic systems as appropriate to the requirements of a specificapplication can be utilized in accordance with embodiments of theinvention. Further, although various components (e.g., tank, pump,valves) are discussed above with respect to FIG. 4, any of a variety ofcomponents as appropriate to the requirements of a specific applicationcan be utilized in accordance with embodiments of the invention. Forexample, various components discussed above with respect to FIG. 4 couldbe interchanged as appropriate to the requirements of a specificapplication in accordance with embodiments of the invention. Further,although specific valve setting values are discussed above with respectto FIG. 4, various valve setting values as appropriate as appropriate tothe requirements of a specific application can be utilized in accordancewith embodiments of the invention. Raising and lowering truck beds usingpower units with manual override controls in accordance with embodimentsof the invention are discussed further below.

Raising and Lowering Truck Beds with Hydraulic Power Units

A power unit with manual override control may be configured to activatea hydraulic cylinder to raise or lower a truck bed by transitioninghydraulic fluid between a first and second chambers of a hydrauliccylinder and a tank of the power unit. A schematic diagram illustratinga hydraulic power unit with manual override control when the hydrauliccylinder is raising a truck bed in accordance with an embodiment of theinvention is illustrated in FIG. 5. The schematic diagram 500 of thepower unit is shown connected to a hydraulic cylinder 202 with a raisingtruck bed 216. In many embodiments, the motor 408 may be powered on andprovide power to the pump 407B thereby turning the pump 407B and routingfluid from the tank 407A to the first solenoid valve 402 in a secondposition 453. For example, in various embodiments, the first solenoidvalve 402 may energize and transition from the first position 452 to thesecond position 453 and allow the fluid from the pump 407B to bedirected to the open end of the control check valve 450 of the secondsolenoid 403A in its first position. The hydraulic fluid may then exitthe A port 409 through a first hose connecting the A port 409 to thebottom port of the hydraulic cylinder. Thus, the hydraulic fluid mayenter through the blind end of the cylinder and apply additional forceon to the piston to extend the piston rod raising the truck bed.

In further reference to FIG. 5, since this is a double acting cylinder,there is hydraulic fluid in the second chamber may be returned back tothe tank 407A. In many embodiments, the hydraulic fluid from the secondchamber may get pushed out of the top port of the hydraulic cylinderthough a second hose connecting to the B port 410 of the power unit. Insuch embodiments, the hydraulic fluid may be routed through the checkvalve 403B and through Cartridge 4W2P solenoid valve 402 in firstposition 452 and overcome the preset pressure of a second relief valve404 and allow the hydraulic fluid to flow through second relief valve404 and return back to the tank 407A.

A schematic diagram illustrating a hydraulic power unit with manualoverride control when the hydraulic cylinder is lowering a truck bed inaccordance with an embodiment of the invention is illustrated in FIG. 6.The schematic diagram 600 of the power unit is shown connected to ahydraulic cylinder 202 with a lowering truck bed 216. In manyembodiments, the motor 408 may be powered on and provide power to thepump 407B thereby turning the pump 407B and routing fluid from the tank407A to the first solenoid valve 402 in a first position 452. Forexample, in various embodiments, the first solenoid valve 402 mayenergize and transition from the second position 453 to the firstposition 452 and allow the hydraulic fluid to flow from pump 407B and bedirected to the open end of the second check valve 403B. The hydraulicfluid may then exit the B port 410 through a second hose connecting theB port 410 of the power unit to the top port of the hydraulic cylinder.The hydraulic fluid may enter through the rod end of the cylinder andapply additional force onto the piston to retract the piston rodlowering the truck bed.

In further reference to FIG. 6, since this is a double acting cylinder,the hydraulic fluid in the first chamber may be returned back to thetank 407A. In many embodiments, the hydraulic fluid from the firstchamber may get pushed out of the bottom port of the hydraulic cylinderthough a first hose connecting to the A port 409 of the power unit. Insuch embodiments, the second solenoid valve 403A may be in a secondposition (i.e., loading a control single-directional connector 451) thatallows hydraulic fluid to flow through the second solenoid valve 403Aand routes the fluid to the first solenoid 402 in its first position452. In various embodiments, the first position 452 of the firstsolenoid 402 routes the fluid to overcome the preset pressure of thesecond relief valve 404 and allows the hydraulic fluid to flow throughsecond relief valve 404 and return back to the tank 407A.

Although specific hydraulic power units with manual override controlsfor raising and lowering truck beds are discussed above with respect toFIGS. 5-6, any of a variety of hydraulic power units with manualoverride controls for various hydraulic systems as appropriate to therequirements of a specific application can be utilized in accordancewith embodiments of the invention. Further, although various components(e.g., tank, pump, valves) are discussed above with respect to FIGS.5-6, any of a variety of components as appropriate to the requirementsof a specific application can be utilized in accordance with embodimentsof the invention. For example, various components discussed above withrespect to FIGS. 5-6 could be interchanged as appropriate to therequirements of a specific application in accordance with embodiments ofthe invention. Further, although specific valve setting values arediscussed above with respect to FIGS. 5-6, various valve setting valuesas appropriate as appropriate to the requirements of a specificapplication can be utilized in accordance with embodiments of theinvention. Lowering truck beds by activating manual override duringpower loss in accordance with embodiments of the invention are discussedfurther below.

Lowering Truck Beds by Activating Manual Override

A power unit with manual override control may be configured to lower araised truck bed when the power unit has malfunctioned. For example, apower unit, without power, may be configured to lower a truck bedwithout overflowing the hydraulic fluid. A schematic diagramillustrating a hydraulic power unit with manual override control whenthe hydraulic cylinder is lowering a truck bed without power inaccordance with an embodiment of the invention is illustrated in FIG. 7.The schematic diagram 700 of the power unit is shown connected to ahydraulic cylinder 202 with a lowering truck bed 216. In manyembodiments, the motor 408 may be off since the power unit is withoutpower. In such embodiments, an operator may activate the manual overridefunction using the manual override input device 411 of the manualoverride control unit 403. In some embodiments, the manual overrideinput device 411 may be, for example, a knob that may be turned or abutton that may be pushed, turned or pulled.

In further reference to FIG. 7, since this is a double acting cylinder,there may be hydraulic fluid in the first chamber that may berecirculated back to the second chamber and once the second chamber hasfilled up, then the remaining hydraulic fluid may return back to thetank 407A. In many embodiments, the hydraulic fluid in the first chambermay be forced out of the bottom port of the hydraulic cylinder through afirst hose connecting to the A port 409 of the power unit due to acombination of gravity, mechanical advantage, and the weight of thetruck bed 216 pushing on the piston rod. In such embodiments, the secondsolenoid valve 403A may be in a second position (i.e., loading a controlsingle-directional connector 451) that allows hydraulic fluid to flowthrough the second solenoid valve 403A to the first solenoid valve 402.In many embodiments, the second solenoid valve 403A may switch from itsfirst position to its second position in response to an operatoractivating the manual override using the override input device 411.Further, the first solenoid valve 402 may be in a first position 452that redirects the hydraulic fluid through the first solenoid valve 402to the first check valve 405. In many embodiments, the fluid may berouted out of the B port 410 since other paths are the closed end of thesecond check valve 403B and the third relief valve 406. In variousembodiments, the second chamber created low pressure (vacuum) whichallows for the hydraulic fluid is thus routed out of the B port 410through a second hose and enters the second chamber via the top port ofthe hydraulic cylinder. Once the second chamber is filled, the internalpressure within the second chamber may build to overcome a predeterminedpressure on the second relief valve 404 and thus allowing any remainderof the hydraulic fluid from the first chamber to return to the tank 407Bwithout overflowing the system.

Although specific hydraulic power units with manual override controlsfor lowering truck beds by activating manual override during power lossare discussed above with respect to FIG. 7, any of a variety ofhydraulic power units with manual override controls for varioushydraulic systems as appropriate to the requirements of a specificapplication can be utilized in accordance with embodiments of theinvention. Further, although various components (e.g., tank, pump,valves) are discussed above with respect to FIG. 7, any of a variety ofcomponents as appropriate to the requirements of a specific applicationcan be utilized in accordance with embodiments of the invention. Forexample, various components discussed above with respect to FIG. 7 couldbe interchanged as appropriate to the requirements of a specificapplication in accordance with embodiments of the invention. Further,although specific valve setting values are discussed above with respectto FIG. 7, various valve setting values as appropriate as appropriate tothe requirements of a specific application can be utilized in accordancewith embodiments of the invention. While the above description containsmany specific embodiments of the invention, these should not beconstrued as limitations on the scope of the invention, but rather as anexample of one embodiment thereof. It is therefore to be understood thatthe present invention may be practiced otherwise than specificallydescribed, without departing from the scope and spirit of the presentinvention. Thus, embodiments of the present invention should beconsidered in all respects as illustrative and not restrictive.

What is claimed is:
 1. A power unit with manual override control for ahydraulic device having an initial state, the power unit comprising: atank for storing hydraulic fluid that moves between a first chamber anda second chamber of the hydraulic device; a pump configured to connectto a motor having a powered on and a powered off configuration, whereinthe motor provides power to the pump to route the hydraulic fluid in andout of the tank in moving the hydraulic fluid between the first chamberand second chamber of the hydraulic device; and a manual overridecontrol unit, wherein activation of the manual override control unitreturns the hydraulic device to the initial state.
 2. The power unit ofclaim 1 further comprising an A port, wherein the A port is configuredto connect to the first chamber of the hydraulic device to allow thehydraulic fluid to enter and exit the first chamber and a B port,wherein the B port is configured to connect to the second chamber of thehydraulic device to allow the hydraulic fluid to enter and exit thesecond chamber.
 3. The power unit of claim 1, wherein the manualoverride control unit comprises a solenoid valve configured to connectto the first chamber of the hydraulic device, wherein the solenoid valveincludes a first position and a second position.
 4. The power unit ofclaim 3, wherein the first position of the solenoid valve loads acontrol check valve having an open end and a closed end.
 5. The powerunit of claim 4, wherein the second position of the solenoid valve loadsa control single-directional connector.
 6. The power unit of claim 3,wherein the activation of the manual override control unit shifts thesolenoid valve between the first position and the second position. 7.The power unit of claim 6, wherein the activation of the manual overridecontrol unit causes hydraulic fluid to exit the first chamber.
 8. Thepower unit of claim 7, wherein the hydraulic fluid exits the firstchamber with assistance from gravity.
 9. The power unit of claim 7,wherein the hydraulic fluid exiting the first chamber is routed to thetank.
 10. The power unit of claim 7, wherein the hydraulic fluid exitingthe first chamber creates a low pressure vacuum in the second chamber.11. The power unit of claim 10, wherein the low pressure vacuum in thesecond chamber causes the hydraulic fluid to enter the second chamber.12. The power unit of claim 11, wherein an internal pressure within thesecond chamber increases to apply pressure for the hydraulic fluid toroute to the tank.
 13. The power unit of claim 7 further comprising atleast one relief valve, wherein the at least one relief valve isconfigured to open when pressure across the at least one relief valvereaches a relief valve setting of the at least one relief valve.
 14. Thepower unit of claim 13, wherein the hydraulic fluid exiting the firstchamber creates pressure to overcome the relief valve setting of the atleast one relief valve allowing hydraulic fluid to route to the tank.15. The power unit of claim 3, wherein the manual override control unitfurther comprises a check valve comprising an open end and a closed end,wherein the closed end of the check valve is configured to connect tothe second chamber of the hydraulic device and wherein the check valveis configured to allow hydraulic fluid to flow in one direction andblock flow in an opposite direction so long as pressure across the checkvalve is below a check valve setting.
 16. The power unit of claim 15further comprising a solenoid valve connected to the pump having a firstposition a second position.
 17. The power unit of claim 16, wherein thesolenoid valve connected to the pump connects the pump to the open endof the check valve when the manual override control unit is activated.18. The power unit of claim 1, wherein the manual override control unitfurther comprises an override input device.
 19. The power unit of claim18, wherein the override input device is activated via a directconnection.
 20. The power unit of claim 18, wherein the override inputdevice is activated via a wireless connection.